This paper contains the first part of a report that details the findings of 256 past and present high-occupancy-vehicle (HOV) treatments. The procedures followed and the major conclusions found concerning the 19 specific HOV treatment types studied are presented. Some of these conclusions are that only four treatments (park-and-ride lots, separate roadways, contraflow freeway and arterial lanes, and preferential bypasses at metered ramps) produced the impacts that were expected. Another seven treatments either produced mixed results or had no effect, and for the remaining six treatments either no reportable data had been collected or they had never been implemented. Findings concerning specific HOV treatments were as follows: transit malls and automobile-restricted zones must have an operating transit system in the street and a major pedestrian generator to be effective; reserved-lane operations must not affect reverse-flow traffic and should be physically separated from peak-direction traffic to be effective; contraflow lanes usually have safety problems during off-peak hours or where major turning movements or pedestrian activity exists; concurrent-flow lanes usually need major transit use or a large increase in occupancy to be effective; and finally, a much greater effort must be made by traffic engineers, planners, and researchers to obtain pertinent information about HOV preferential treatments. Volume 2 of this report (available from the new jersey department of transportation) contains a comprehensive bibliography along with a listing of each HOV treatment cited, including the year implemented, size, priority cut-off, hours of operation, current status, and any before-and-after data concerning the impacts that the treatments may have had.
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